Efficiency of Corrugated Cardboard as a Building Material

1

Efficiency of Corrugated Cardboard as a Building

Material

Morad Abdel-Kader Abdel-Mohsen1

, Ahmed A. Faggal2

and Yara S. El-Metwally3

1 Professor,

2Associate Prof., Dept of Architectural Engineering, Ain Shams University

3Teaching Assistant, Dept of Architectural Engineering, British University

Abstract

This study examines the feasibility of using corrugated cardboard as a building

material in order to develop an efficient design for an emergency portable shelter.

Corrugated Cardboard has great potentials that enable it to be an alternative to the

existing materials for temporary structures. Due to its light weight, it can be easily

assembled, disassembled and relocated to other destinations. In this paper a

literature review on corrugated cardboard, presenting its historical background, its

characteristics, potentials and limitations, is given. Next, an analytical study is

presented, from which a cardboard shelter is proposed as a solution for the lack of

adequate emergency shelters in Egypt. By using Design Builder software as a

simulation tool, the thermal performance of the building envelope of the shelter is

evaluated in order to examine the adaptability of using cardboard in Egypt.

Different alternatives are tested one by one over the year on 21st

of March, June,

September and December. The output data is analyzed and compared with each

other to address which of these systems tends to achieve better indoor thermal

temperature. A comparison between the proposed systems and an economic brick

shelter with the same dimensions is also conducted to evaluate the thermal

performance of each. The results show that corrugated cardboard has the ability to

adapt to Egypt's climate and to be a feasible construction material.

Keywords: corrugated cardboard, shelter, building envelope, thermal performance.

1. Introduction

Nowadays, corrugated cardboard is not just limited to packaging purposes, but it

is more being involved in other different fields as in construction and indoor

furniture. Recently, constructing shelters from corrugated cardboard panels

represents an innovative approach in the construction industry, although it appeared

many years ago. Cardboard structures can be used for permanent living purposes or

as temporary emergency houses in disasters, which could be a solution for the

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insufficient tents offered to homeless after a disaster, that are neither comfortable

nor safe. Selecting an adequate material for emergency shelters is one of the main

parameters that affect its success. Emergency shelters should be flexible, portable,

light weight and economically efficient structures. Corrugated cardboard adopts a

variety of these characteristics and has much more potentials that could motivate

expertise to develop it further. In structural terms, cardboard has considerable

strength, stability and stiffness in comparison to other building materials. All these

potentials, as well as, the limitations such as its weakness to humidity and fire are

introduced in the paper to reflect cardboard's performance as a building material.

The empirical part of this study is the evaluation of the thermal performance of

the envelope of three different cardboard shelters that vary in their thicknesses and

their panels' layers and a brick shelter. The target of this variation is testing the

influence of the different panel's thickness, as well as, examining the impact of air

gap between the layers of the cardboard panels. In addition, the cardboard shelter is

compared with economic brick shelter to testify the thermal adaptability of both

systems along the year without using any kind of insulation or shading devices.

2. Historical Background of Cardboard in Construction

The application of cardboard in construction began many years ago, since the 2nd

World War and was developed through the years. This development can be

summarized in three main periods:

1. The birth of cardboard building prototypes from 1944 till 1990;

2. The appearance of the Japanese Architect Shigeru Ban; and

3. The development of contemporary prototypes and approaches during the last

decade.

The first known cardboard building is the1944 House, Fig. 1, that was

constructed out of 2.5 cm thick corrugated cardboard produced from waste paper.

Sulphur was applied to the content of cardboard to enhance its rigidity; besides,

they were painted with several layers of fire-proof paints.

Fig. 1 The 1944 House (Ayan, 2009).

Unfortunately, the use of cardboard in construction was limited in the first period

due to the lack of research and development of the material performance against

water and fire. However, many architects had later significant impact on cardboard

usage in construction. One of these pioneers is Buckminster Fuller (Ayan, 2009)

who had in the 1950s an innovative approach and experimental application of

cardboard components in architecture. He had a vision of creating environmentally

sustainable building without ignoring economic aspects. Hence, he arrived to the

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philosophy more-with-less aiming to solve global problems. Fuller was concerned

with ecological sustainable building materials and renewable energy sources

challenging traditional building methods. The choice of cardboard was due to its

low cost, its suitability for mass production and its minimal environmental impact.

Architects and engineers were inspired by Fuller innovative ideas of using

cardboard in the construction and started their research on maintaining the structural

strength and stiffness of cardboard when exposed to external weather conditions,

humidity and fire. In these experimental early prototypes, cardboard was used

structurally either as the primary element or as secondary supporting element. They

found out that geodesic domes and other polyhedral macro forms of cardboard are

efficient solutions for rigidity. As for weatherproofing and sealing they added

substances such as boiled linseed oil, copal varnish, polyurethane paints, resin-

based paints, fiberglass and concrete on the outer surface of the structure.

Nevertheless, the success of these early cardboard buildings did not continue long,

it was not further developed despite these efforts. Another reason beyond the drop

off cardboard usage in buildings is the introduction of other new alternative

building materials in the late 1950’s, as laminated plastic and Formica.

The second period of cardboard development (Shigerubanarchitects.com, 2013)

was under the leadership of the Japanese humanitarian architect Shigeru Ban, who

is well known throughout the world for his innovative designs. Ban established in

1995 an NGO for the sake of providing cheap housing for the victims of natural

disasters that have minimal environmental impact. He created a number of

successful emergency shelters out of cardboard; one of the most known projects is

the “Paper Log House" in Japan, shown in Fig. 2.

Fig. 2 Paper Log House in Japan (House, 2014).

Ban projects succeeded to prove cardboard's structural strength and stiffness.

Several of his projects have been certified by local and state official authorities

worldwide. In the last decade an increased interest in cardboard experiments in

architecture had been noticed after Ban's successful work. The Westborough

Primary School in England, designed by architects Cotterel & Vermeulen in 2001

and the Cardboard House, designed by architects Stutchbury and Pape in 2004 are

examples of modern applications.

3. Characteristics of Corrugated Cardboard

Cardboard is a paper production with a number of different layers of fibers. New

virgin fibers such as cellulose (sulphate or sulphite, bleached or non-bleached) can

be added to wood pulp, recycled fibers and other additives such as aluminum

sulphate, kaolin, starch and synthetic latex to produce cardboard. Corrugated

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cardboard is composed of a sandwich structure; a corrugated medium layer (flipped

layer) of paper called "fluting" placed between two layers of flat paper called

"liners" or "plies", as shown in Fig. 3.

top outer liner

Flute

bottom outer liner

Fig. 3 Basics of corrugated cardboard (Ayan, 2009).

4. Classification of Corrugated Cardboard

There are a variety of corrugated cardboards that can be classified according to

several different characteristics, including construction (single face, single wall,

double wall, etc), flute size, burst strength, edge crush strength, flat crush strength,

basis weights of its components, surface treatments, impregnation, printing and

coatings (Ayan, 2009). In the following, the classification of cardboard according to

fluting and according to form are discussed.

Classification according to form

Corrugated Cardboard can be formed in tubes with a maximum thickness of

16mm and a maximum diameter of 600mm.The tube length is not limited by the

manufacture process, but by transportation. It can also be produced as panels with a

variety of forms; they may appear as simple corrugated panels or as a corrugated

honeycomb panels that are made by sandwiching a honeycomb structure between

sheets of paper. The Panels have a width between 1.2m and 1.5m and a length

between 2.4m to 3.6m. The thickness differs from single layer sheets of 1mm thick

to 65mm thick sheets.

Fig. 4 Stacked cardboard tubes

(ALMUT, 2009).

Fig. 5 Honeycomb structure produced by

corrugated cardboard machine (Ayan, 2009).

Classification according to fluting

Corrugated cardboard consists of multiple layers of fluting with a variety of flute

sizes, table 1. The most basic type is the single wall cardboard that consists of one

piece of fluted paper sandwiched between two linerboards (Lithotech.ca, 2013). The

Flute's thickness may range from 0.8-4.8mm and weights between 112-180g/m2,

while liner weights between 115-350g/m2 (Paulapuro, 2000).

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Table 1 Flute Types of corrugated cardboard sheets (O'neil, 2009)

Type Description Image

A-Flute The original flute and has the

highest arch height with 110± 10

flutes per meter. It has excellent

stiffness and short column crush

resistance.

(Packaging-gateway.com, 2014)

B-Flute Thinner than A-type, but has good

compression strength, compactness,

printability and is cost effective. It

has around154 ± 10 flutes per meter.


C-Flute Thicker than B-flute but thinner than

A-flute. It is the most commonly

used flute type. It consists of around

128 ± 10 flutes per meter.


E-Flute A very thin flute and has about 290

flutes per meter. It offers excellent

crush resistance and printability. (Packaging-gateway.com, 2014)

F-Flute The newest type in the packaging

industry and is just over half the

thickness of E-flute. It consists of

the lowest fiber content of all other

flutes.


BC-Flute

(double

wall)

The combination of B and C flutes

offers greater compression and

stacking strength.

(Dotorial.com, 2014)

5. Potentials of Corrugated Cardboard

Corrugated cardboard is provided with multi characteristics that justify its use a

proper building material. This is illustrated in the following.

Weight

Cardboard has a light weight which facilitates its transport, assembly and

disassembly.

Durability

Experiments prove that corrugated cardboard has considerable strength, stability

and stiffness in comparison with other common building materials; it can resist

significant structural loads. The existence of wood fibers in its content improves its

strength and resilience. Cardboard is puncture resistant and does not tear easily. The

arched design of the interior fluting enhances its durability to resist more external

force. The liners of the corrugated cardboard provide bending stiffness, while flutes

provide shear stiffness. (ALMUT, 2009)

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Recycability

Cardboard is produced using virgin cellulose fibers containing 43% recycled

fibers. After usage of cardboard it can be recycled or reused for other purposes. The

Cardboard School Project in the U.K. has proven that 90 percent of the corrugated

cardboard are recyclable, the fibers may be recycled up to seven times before it

loses its resilience. (Gribbon and Foerster, 2008)

Flexibility

Corrugated cardboard is a very flexible material; it can be cut and folded into

infinite sizes and shapes. Prefabricated cardboard buildings will offer flexibility in

the design which allows users to adapt by adjusting the space according to their

needs. The space can be easily extended by attaching cardboard units to it.

Environmental impact

Cardboard has minimal impact on the environment during the production

process; it does not consume much energy if compared with other materials. Hence,

less emission is expected to be produced. In addition, it is produced from a

renewable resource, which limits the depletion of non-renewable resources. All

materials used in the manufacturing of cardboard are natural and non-toxic.

Prefabrication, pre-assembly and mass customization allow optimum usage of the

material, and minimize onsite waste and labor. Moreover, lightweight cardboard

components and panels decrease the transportation costs.

Construction efficiency

Prefabricated cardboard building elements allow a fast, simple, inexpensive

manufacturing, and also minimize time spent on the construction site.

Efficiency is gained by decreasing the number of building materials, as cardboard

alone can satisfy all the functions of a building’s exterior skin. This elimination of

multi-layering saves costs and simplifies the construction process. (Ayan, 2009)

Cost Efficiency

Cardboard as a raw material is relatively inexpensive. However, cost efficiency

can be achieved by mass production of repetitive and standardized shapes. (Gribbon

and Foerster, 2008, p.98)

Thermal insulation

Corrugated cardboard has insulating properties due to the fluting design of its

interior. The flutes catch air between the two liners, extending the amount of time

needed to transfer heat energy from the exterior to the interior; it stores heat

temporarily. Another aspect is the cellulose fibers that are used in the cardboard

production have low thermal conductivity and strong insulating properties.

Acoustic insulation

Extensive layering of corrugated cardboard and specially the air gaps between

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flutes or honeycomb structure allows significant acoustical insulation.

(Schreuders and Salmon et al., 2008)

6. Limitations of Corrugated Cardboard

Cardboard has some limitations that can affect its performance if not treated

properly, some of this limitations are given in the following.

Moisture Resistance

Moisture has a negative impact on cardboard's strength (Ayan, 2009). When

cardboard is exposed to humidity or direct water, the bonds between the paper

fibers can be destroyed. To enhance cardboard water resistance, chemical additives

can be used during the pulp production process. The only disadvantage of these

chemical treatments is that it affects its recyclability. Another option is adding a

coating on top of the cardboard, as a thin layer of recycled Polyethylene

Terephthalate (PET). This coatings protect cardboard from moisture as well as from

chemical dangers. Besides, the roof should have an angle of slope, even a flat roof

has a slope.

Fire Resistance

Cardboard reacts in a similar way to fire as wood; it is flammable if not treated

appropriately. Fortunately, cardboard contains a certain amount of chalk-like

material, an excellent fire retardant, as a result from the ink traces left in the

recycling process, which slightly enhances its fire resistivity. Besides, cardboard

can be made with extra protection, that are based on (boric) salts. Adding these

materials does not affect the ability to recycle the material.

Insects

Cardboard is a cellulose material that requires protection from insects.. This can

also be solved by applying additives during manufacturing process. (Van Dooren

and Van Iersel, 2008)

7. Simulation of a Cardboard shelter in Egypt

With the use of Design builder software the thermal performance of three

different corrugated cardboard shelters have been tested and then compared to an

economic brick shelter without changing the shelter dimension and openings. The

three initial models, as well as, the brick shelter were tested over the year on 21st

of

March, June, September, and December. The aim of this simulation is to test the

adaptability of cardboard shelters in Egypt and to compare the results of the

different wall and roof panels to visualize their effect upon the indoor thermal

comfort1.

1 According to Givoni chart in his book" Climate in Building and Urban Design, p.38", the thermal comfort

limits in a hot developing country ranges from 20˚C to 29˚C. The upper limit decreases gradually to 27˚C, if

the relative humidity exceeds 50%.

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The proposed initial model consists of a single living space with an area of 14m2.

According to the United Nations High Commissioner for Refugees (UNHCR)

standards, this space is adequate for a family of 4 persons, where each person has an

area of 3.5m2. The shelter is assumed to take a rectangular form. Hence, its

dimensions are worked out as 4m (L) × 3.5m (w) × 2.8m (h). The 4m wall side is

directed towards the north. In all case studies the skin is the structure. Fig. 6 shows

a primary plan for proposed living space in the simulation. The construction details

of the different proposed shelters, as well as, the brick shelter and openings details

are introduced in Table 2.

Fig. 6 Plan of the Simulation model and its Orientation.

Table 2 Proposed dimensions for Living Space as used in simulations

Shelter parameters

Location Cairo, Egypt

Dimensions 4m (L)×3.5m (w)×2.8m (h) Floor Area = 14 m2 Volume = 39.2 m

3

Construction

of cardboard

shelter

Walls and roof consist of panels of corrugated Cardboard:

Case A - 3.92cm wall thickness consisting of a honeycomb sandwich

structure 3cm between two A-Flute boards with a thickness of 0.46cm

each. The roof consists of the same panels of the wall.

Case B - 5.76cm wall and roof thickness consisting of honeycomb

sandwich structure 3cm between triple layers of A-Flute boards on

each side.

Case C - A 5.76 wall and roof system of a triple A-flute with an air

gap of 3cm in between instead of the honeycomb structure.

Construction

of brick

shelter

Wall Layers: 25cm brick, 2cm mortar and 2cm paint

Roof Layers: 12cm concrete slab, 6cm Sand, 2cm Mortar, 2cm tiles

Openings Window: single blue glazing with a thickness of 6mm

Window Frame: wooden frame, Window height: 1.5m, Sill height:

0.8m

Door: Cardboard door.

The door is above floor level with 0.1m and is 2.1m high.

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8. Results of Initial Models

1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am 12pm 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm 12am

Indoor Temperature˚C 15.97 15.90 15.85 15.72 15.53 15.32 15.15 15.29 16.21 18.22 21.27 23.74 25.67 26.06 25.45 24.91 24.03 23.06 22.22 21.22 20.09 18.93 17.8 16.7

Outside Dry Bulb˚C 16.85 16.90 16.17 15.85 15.57 15.27 15.05 15.00 15.75 15.75 16.75 18.88 20.10 20.45 21.23 21.88 21.17 20.67 19.70 17.60 16.55 15.35 15.00 14.93

Relative Humidity% 50.86 45.08 40.89 38.76 38.79 40.24 41.97 42.43 40.45 35.95 29.05 22.59 21.68 23.64 21.49 19.77 21.41 23.65 26.83 31.44 36.25 32.09 46.3 50.6

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Comfort zone (temperature )

Fig. 7 Thermal simulation results of Case study A in March.

From the results in Fig. 7 for case A in March, it can be noted that from 1am to

2am the indoor temperature is lower than the outdoor by 1˚C. Both line graphs

converge from 3am to 9am. Starting from 10am till 12am the indoor temperature

increases much more than the outdoor temperature with a maximum difference of

6˚C at 2pm. The minimum indoor temperature reaches 15˚C at 7am and the

maximum achieves 26˚C at 2pm. The relative humidity differs during the day from

20 % to 50%. This month shows 11 hours within the thermal comfort limits.


Indoor Temperature˚C 27.90 26.41 25.16 24 23.17 22.75 22.91 24.25 26.14 28.35 31.41 35.64 39.70 41.81 42.69 42.38 41.71 40.65 38.77 36.51 34.55 32.76 30.87 29.37



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Case A - 21st June

Comfort zone (temperature

Fig. 8 Thermal simulation results of Case study A in June.

The results of June for case A, Fig. 8, can be categorized in three phases along

the day. The first period starts from 1am until 4am in which the indoor temperatures

is higher by an average of 1.5˚C than the outdoor temperature. Then, the indoor

temperature drops until it becomes lower than outdoor by an average of 2˚C from

5am up to 9am. The third period begins from 10am with a great increase of the

indoor temperature to be above the outdoor by 2˚C, until it reaches a difference of

6˚C at 1pm to 4pm. This value decreases gradually till the end of the day. The

maximum indoor temperature is about 43˚C while the minimum indoor temperature

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is 23˚C. The relative humidity varies along the day from 21% to 66%. Thermal

comfort is achieved during 10 hours through the day.

The results of September for case A, Fig. 9, indicate a slight difference between

indoor temperatures and outdoor temperatures from 1am till 9am. From 10am the

two line graphs start to diverge with a minor indoor heat gain. From 12pm to 4pm

the indoor temperature increases rapidly by an average of 6.5˚C compared to the

outdoor. This gain starts to reduce slightly from 5pm till the end of the day, when

both line graphs meet again. The minimum indoor temperature is 20˚C at 6am

while the maximum reached is 38˚C at 3pm. The relative humidity varies along the

day from 30-87%. Comparing the above results with the thermal comfort, 15 hours

were obtained within the comfort limits considering the temperature and relative

humidity comfort limits.



Outside Dry Bulb˚C 23.25 22.25 21.55 21.1 21 20.4 19.98 20.42 21.65 23.5 26.1 27.7 29.5 30.75 30.55 30.85 31 30.1 28.45 27.25 26.25 25.25 25 24.25


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Case A - 21st September


Fig. 9 Thermal simulation results of Case study A in September.



Outside Dry Bulb˚C 11.85 11.25 11.3 11.1 11 10.4 10.05 11.05 10.35 10 11.5 12.45 12.9 13.75 13.85 13.95 14 13.02 12.18 12 12.15 12.05 12 11.55


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Case A - 21st December


Fig. 10 Thermal simulation results of Case study A in December.

The results of December for case A, Fig. 10, show higher values of the indoor

temperature than the outdoor's during the day. From 1am to 12pm it is by an

average of 1.5˚C higher than the outdoor, this value increases to 4˚C from 1pm till

7pm, then it falls to 1.5˚C at the end of the day. The minimum indoor temperature is

about 12˚C and the maximum is 18˚C. The relative humidity ranges from 40-69%.

This month is out of comfort range according to the comfort limits.

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˚CCaseB -21stMarch

Comfort zone ( temperature)

Fig. 11 Thermal simulation results of Case B in March.

For case B in March, Fig. 11, heat gain is noticed along the day with variation; in

the first 12 hours of the day the indoor temperature is a little higher than the outdoor

by 0.6˚C. In the remaining 12 hours the difference increases to be around 3.5˚C.

The minimum indoor temperature is 16˚C at 8am and the maximum is 24 ˚C at

4pm. The relative humidity differs through the day from 21 % to 47%. 11 hours

are achieved within the comfort limits.





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˚CCase B- 21st June


Fig. 12 Thermal simulation results of Case B in June.

Four time frames are noticed in Fig. 12, for case B in June, in which 6am, 9am,

1pm are considered as turning points. The first frame is from 1am to 5am, where the

indoor temperature has a higher value than the outdoor by an average value of

3.2˚C. From 6am to 8am a heat loss indoors occurs by 1.3˚C. Indoor and outdoor

temperature remains almost similar 9am until 12pm. The curves exchange their

positions again from 1pm till 12am, so that the indoor temperature gets higher than

the outdoor by 2.2˚C. The maximum indoor temperature in this month is 40˚C from

5pm to 6pm; which are also the peak hours outdoors and the minimum reaches

24˚C. The relative humidity varies from 23 % to 61%. 9 hours are within the

comfort limits.

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˚CCase B - 21st September


Fig. 13 Thermal simulation results of Case B in September.

The results of Fig. 13 for case B in September, show higher values in the indoor

temperatures compared to the outdoor by except from 9am to11am where both line

graphs are almost alike. From 1am to 8am and from 12pm to 12am the indoor

temperature is above the outdoor by an average of 2.3˚C .The minimum indoor

temperature is 21˚C and the maximum 34˚C. The relative humidity ranges from

36% to 83%. 15 hours are within the thermal comfort limits.


Indoor Temperature˚C 13.38 13.06 12.85 12.7 12.55 12.37 12.2 12.53 12.58 12.76 13.26 14 14.98 16.05 16.84 17.14 17.17 16.78 16.28 15.76 15.32 14.93 14.57 13.89



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˚CCase B- 21st December


Fig. 14 Thermal simulation results of Case B in December.

The results of December for case B, Fig. 14, show higher values in the indoor

temperatures compared to the outdoor by an average of 2.5˚C through the day. The

minimum indoor temperature is 12˚C at 7am and the maximum 17˚C. The relative

humidity ranges from 41% to 67%. This month did not fulfill thermal comfort.





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˚CCase C -21st March


Fig. 15 Thermal simulation results of Case C in March.

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From the results of case C in March, a heat gain is noticed indoors along the day

except from 11am till 1pm, where the indoor temperature gets lower than the

outdoor by 0.5˚C. The detected heat gain starts from 1am to 10am by an average of

2˚C, from 1pm to 6pm by 0.5˚C and finally the outdoor temperature decreases

rapidly compared to the indoor to be lower than it by 5˚C. The minimum indoor

temperature is about 17˚C and the maximum is about 23˚C. The relative humidity

differs through the day from 23% to 43%. 12 hours are achieved within the comfort

limits.





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˚CCase C - 21st June

Fig. 16 Thermal simulation results of Case C in June.

From Fig. 16 for case C in June, in the first period of the day from 1am to 7am a

heat gain indoors is observed by an average of 4˚C. From 8am the curves start to

exchange their positions, the outdoor temperature exceeds the indoor by an average

of 1.8˚C till 7pm. Finally the outdoor temperature decreases more than the indoor to

be lower than it by 2.2˚C. The maximum indoor temperature in this month is about

36˚C from 5pm to 8pm and the minimum 26˚C. The relative humidity varies from

29% to 58%. 8 hours are only within the comfort limits.





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˚CCase C - 21st September


Fig. 17 Thermal simulation results of Case C in September.

For case C in September, Fig. 17, from 1am until 9am the inside temperature is

higher than the outside by an average of 2.5˚C. The the two line graphs intersect at

10am then the outdoor temperature increases to be above the indoor by 2˚C until

5pm. From 6pm to 12am the outdoor temperature decreases and get lower than the

indoor by 2˚C. The minimum indoor temperature in this month is about 23˚C while

the maximum reaches 31˚C. The relative humidity varies along the day from 42% to

76%. 17 hours were conducted within the comfort limits.

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˚CCase C- 21st December


Fig. 18 Thermal simulation results of Case C in December.

The results of case C in December, Fig. 18, show higher values in the indoor

temperatures than the outdoor by an average of 2.7˚C during the day. The minimum

indoor temperature is 13˚C at 7am and the maximum 17˚C. The relative humidity

ranges from 43% to 62%. No thermal comfort is detected in this month.





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˚CBrick Shelter- 21st March

\\\ Comfort zone ( temperature)

Fig. 19 Thermal simulation results of Brick shelter in March.

For a brick shelter in March, Fig. 19, except from 12pm till 4pm, a heat gain is

noticed indoors by an average of 4˚C along the day. Otherwise only a slight

difference appears between indoors and outdoors. The minimum indoor temperature

is about 19˚C and the maximum is about 22˚C. The relative humidity differs

through the day from 26% to 40%. 18 hours are within the comfort limits.


Indoor Temperature˚C 35 34.54 34.14 33.75 33.4 33.09 32.34 31.76 30.77 30.85 31.53 32.5 33.08 33.59 34.29 35.09 35.74 36.37 36.52 36.59 36.54 36.29 35.8 35.48



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˚CBrick Shelter- 21st June


Fig. 20 Thermal simulation results of Brick shelter in June.

15

For a brick shelter in June, Fig. 20, a 9˚C difference between indoor and outdoor

temperature is noticed due to the release of the stored heat. A high fluctuation of

outdoor temperature line graph is noticed. After 1am a thermal loss appears inside

and outside, but the indoor temperature is still above the outdoor by an average of

7˚C. At 12pm both line graphs meet and the indoor temperature gets below the

outdoor by 2˚C. In the last five hours the outdoor temperature drops rapidly to be

lower than the indoor by 4˚C. The maximum indoor temperature is 37˚C and the

minimum 31˚C. The relative humidity is from 28% to 43%. This case is out of

comfort zone.

From the results of a brick shelter in September, Fig. 21, in the first 11 hours of

the day the indoor temperature is higher than the outdoor by an average of 6˚C.

From 12pm to 6pm the line graphs exchange their positions, due to the increase of

the outdoor temperature that gets higher than the indoor by 2˚C. By the end of the

day, from 7pm to 12am the outdoor temperature decreases to be lower than the

indoor by 4˚C. The maximum temperature in this case is 30˚C, while the minimum

is 27˚C. The relative humidity varies from 43% to 60%. 15 hours are within the

comfort limits.





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˚CBrick Shelter- 21st September


Fig. 21 Thermal simulation results of Brick shelter in September.





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Fig. 22 Thermal simulation results of Brick shelter in December.

For a brick shelter in December, Fig. 22, the indoor temperature exceeds the

outdoor by an average of 2.5˚C through the whole day, except from 12pm to 3pm,

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Case A 12.4 12.2 12.08 12.01 11.87 11.73 11.57 11.85 12.06 12.49 13.42 14.91 16.55 17.75 18.24 17.94 17.33 16.32 15.45 14.71 14.17 13.8 13.5 12.87

Case B 13.38 13.06 12.85 12.7 12.55 12.37 12.2 12.53 12.58 12.76 13.26 14 14.98 16.05 16.84 17.14 17.17 16.78 16.28 15.76 15.32 14.93 14.57 13.89

Case C 14.45 14.14 13.90 13.72 13.54 13.35 13.15 13.59 13.61 13.65 13.94 14.22 14.58 15.08 15.63 16.06 16.42 16.46 16.39 16.25 16.07 15.86 15.59 14.93

brick 13.88 13.75 13.64 13.54 13.42 13.28 13.14 13.49 13.45 13.38 13.5 13.56 13.6 13.75 13.9 14.06 14.3 14.37 14.48 14.54 14.59 14.6 14.52 14.08

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where no difference is detected. The maximum indoor temperature is 14.5˚C and

the minimum 13˚C. The relative humidity ranges from 49% to 62%. No hours are in

comfort zone.

9. Discussion

The comparison of the case studies is based on the achieved thermal comfort

hours, the maximum and minimum temperature during the year, relative humidity

and cost. Fig. 23 compares the temperature line-graphs of all above studied cases

with each other, while Table 3 compares between them according to the maximum

and minimum temperature, the relative humidity and the achieved comfort hours

during the four months.


Case A 15.97 15.9 15.9 15.7 15.5 15.3 15.2 15.3 16.2 18.2 21.3 23.7 25.7 26.1 25.5 24.9 24.0 23.1 22.2 21.2 20.1 18.9 17.8 16.7

Case B 17.53 17.17 16.82 16.56 16.31 16.06 15.84 15.75 16.13 17.16 18.92 21.34 22.79 23.75 23.99 24.10 23.80 23.44 23.04 22.47 21.54 20.57 19.59 18.22

Case C 19.17 18.72 18.24 17.87 17.56 17.27 17.01 16.84 16.97 17.45 18.41 19.53 20.62 21.54 22.07 22.42 22.52 22.55 22.68 22.53 22.04 21.49 20.64 19.71

brick 20.98 20.84 20.52 20.26 20.00 19.74 19.50 19.32 19.28 19.36 19.64 19.95 20.15 20.34 20.71 21.13 21.64 21.90 21.16 22.15 22.07 21.91 21.58 21.05

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Case A 27.90 26.41 25.16 24 23.17 22.75 22.91 24.25 26.14 28.35 31.41 35.64 39.70 41.81 42.69 42.38 41.71 40.65 38.77 36.51 34.55 32.76 30.87 29.37

case B 29.83 28.47 27.20 26 25.13 24.45 24.17 24.49 25.35 26.72 28.90 31.68 34.72 37.25 39.03 39.87 40.22 40.00 39.04 37.55 36.01 34.40 32.78 31.29

case C 30.89 29.84 28.82 28 27.07 26.41 25.92 25.87 25.75 26.40 27.51 28.99 30.52 32.20 33.80 35.11 36.05 36.60 36.36 35.86 35.09 34.13 33.04 31.98

brick 35 34.54 34.14 33.75 33.4 33.09 32.34 31.76 30.77 30.85 31.53 32.5 33.08 33.59 34.29 35.09 35.74 36.37 36.52 36.59 36.54 36.29 35.8 35.48

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(b) Comparison in June


Case A 23.74 22.9 22.06 21.28 20.74 20.29 20.31 20.37 21.66 24.41 28.96 33.04 35.92 37.59 37.67 36.58 35.08 33.17 31.15 29.58 28.15 27.01 25.67 24.65

Case B 25.02 24.2 23.4 22.65 22.01 21.43 21.41 21.3 21.69 23.01 25.38 28.31 30.87 32.84 33.89 34.23 33.88 33.11 31.92 30.71 29.55 28.44 27.06 25.98

Case C 25.98 25.28 24.62 24 23.43 22.86 22.82 22.74 22.83 23.31 24.34 25.68 27.09 28.41 29.33 30.12 30.56 30.64 30.34 29.84 29.29 28.57 27.67 26.71

brick 28.77 28.44 28.12 27.82 27.53 27.2 27.23 27.09 27.08 27.17 27.46 27.73 28.07 28.41 28.73 29.19 29.63 29.93 30.02 30.04 30.01 29.87 29.45 29.1

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(c) Comparison in September

Fig. 23 Comparison between all case studies.

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Case A 12.4 12.2 12.08 12.01 11.87 11.73 11.57 11.85 12.06 12.49 13.42 14.91 16.55 17.75 18.24 17.94 17.33 16.32 15.45 14.71 14.17 13.8 13.5 12.87

Case B 13.38 13.06 12.85 12.7 12.55 12.37 12.2 12.53 12.58 12.76 13.26 14 14.98 16.05 16.84 17.14 17.17 16.78 16.28 15.76 15.32 14.93 14.57 13.89

Case C 14.45 14.14 13.90 13.72 13.54 13.35 13.15 13.59 13.61 13.65 13.94 14.22 14.58 15.08 15.63 16.06 16.42 16.46 16.39 16.25 16.07 15.86 15.59 14.93

brick 13.88 13.75 13.64 13.54 13.42 13.28 13.14 13.49 13.45 13.38 13.5 13.56 13.6 13.75 13.9 14.06 14.3 14.37 14.48 14.54 14.59 14.6 14.52 14.08

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Case A 12.4 12.2 12.08 12.01 11.87 11.73 11.57 11.85 12.06 12.49 13.42 14.91 16.55 17.75 18.24 17.94 17.33 16.32 15.45 14.71 14.17 13.8 13.5 12.87

Case B 13.38 13.06 12.85 12.7 12.55 12.37 12.2 12.53 12.58 12.76 13.26 14 14.98 16.05 16.84 17.14 17.17 16.78 16.28 15.76 15.32 14.93 14.57 13.89

Case C 14.45 14.14 13.90 13.72 13.54 13.35 13.15 13.59 13.61 13.65 13.94 14.22 14.58 15.08 15.63 16.06 16.42 16.46 16.39 16.25 16.07 15.86 15.59 14.93

brick 13.88 13.75 13.64 13.54 13.42 13.28 13.14 13.49 13.45 13.38 13.5 13.56 13.6 13.75 13.9 14.06 14.3 14.37 14.48 14.54 14.59 14.6 14.52 14.08

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Fig. 23 Cont.

Table 3 Comparison between Case Studies

Case A Case B Case C Brick

March Thermal Comfort hours 11hrs 11hrs 12hrs 18hrs

Min. Temp 15˚C 16˚C 17˚C 19˚C

Max. Tem 26˚C 21˚C 23˚C 22˚C

RH 20 – 50% 36-81% 23-43% 26 – 40%

June Thermal Comfort hours 10 hrs 9 hrs 8hrs 0

Min. Temp 23˚C 24˚C 26˚C 31˚C

Max. Tem 43˚C 40˚C 36˚C 37˚C

RH 21 -66% 23-61% 29-58% 28-43%

September Thermal Comfort hours 11 hrs 13 hrs 17hrs 15hrs

Min. Temp 20˚C 23˚C 23˚C 27˚C

Max. Tem 38˚C 34˚C 31˚C 30˚C

RH 30-87% 36-83% 42-76% 43-60%

December Thermal Comfort hours 0 0 0 0

Min. Temp 12˚C 12˚C 13˚C 13˚C

Max. Tem 18˚C 17˚C 17˚C 15˚C

RH 40-69% 41-67% 43-62 49-62%

The analysis of the above results can be summarized in the following points:

By increasing the thickness of the cardboard panels the minimum

temperature and minimum humidity elevate, while the maximum

temperature decreases during the year. Accordingly, Case B gives better

results than A in September and June. The more the thickness, the more the

resistance against heat absorption. The thermal comfort hours increase in

September by two hours and decrease in June by one. This variation is due

to the increase of the panel thickness that releases the stored heat slower than

Case A, which warm up the space at the beginning of the day.

Case C differs from B in removing the 3cm honeycomb structure and

leaving the cardboard panels with an air gap in between. The results show

that the minimum temperature in Case C is higher than case B due to the

slow release of the stored heat which results in the increase of the thermal

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comfort hours in March and September. Although the comfort hours were

reduced by an hour in June, still the performance of Case C is higher than

Case B due to the decrease of the indoor temperature during the peak hours.

Besides, the reduction of the material usage, as the honeycomb is replaced

with an air gap, decreases the cost of Case C.

Comparing Case C with an economic brick shelter shows lower fluctuation

in the indoor temperature in the brick shelter because lightweight structures

cool down faster than heavy structures. They are able to gain heat rapidly

and lose it rapidly as well. This explains the increase of the brick shelter’s

minimum temperature in March, June and September compared to Case C.

In June, the brick shelter is out of comfort zone, because it did not get rid of

the stored heat easily during the night. The comfort hours in March are by 6

hours higher and by two hours lower in September than Case C. In

December, the maximum temperature is lower than in Case C. Hence,

Cardboard shelters, especially Case C shows better thermal performance

than brick shelters, due to the fast release of stored heat.

10. Conclusion

This paper has clarified the potentials of cardboard as a building material.

Corrugated cardboard may have some limitations as minimal fire and water

resistance, but adjustments can be achieved during the manufacturing in order to

enhance its performance. Cardboard fulfill the criteria needed for building

emergency mobile shelters; it is light weighted, flexible, durable, sustainable and

cost efficient. Besides, the simulation results show that cardboard shelter have

thermal insulation properties which can make it more adaptable than a brick shelter

in Egypt. Hence, this study holds that it is feasible to employ corrugated cardboard

as a main construction element in Egypt. The 6cm thick wall in Case E gives better

results than a 25cm brick wall, because lightweight structures gain and lose heat

rapidly. In addition, the flutes and materials used in Cardboard increase its

insulating properties. The use of cardboard as an alternative building material not

only satisfies a building’s structural demands, but also fulfills certain environmental

and social demands that make it more potentially and more attractive than standard

building materials.

References

1. Almut, P., 2009, Strengthened Corrugated Paper Honeycomb, Ph.D., Zurich.

2. Eekhout, M., Verheijen, F. and Visser, R. 2008, Cardboard in architecture,

Amsterdam: IOS Press.

3. Gribbon, H. and Foerster, F., 2008, Structural Engineering and Design in

Paper and Cardboard-Approaches and Projects, Cardboard in Architecture,

7, p. 95.

4. Hagercontainers.com, 2014, What is Corrugated? [online] Available at:

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http://www.hagercontainers.com/corr0 [Accessed: 28 Jan 2014].

5. House, P., 2014, DOMESTIC CURRENT: Pin's Case Study: Shigeru Ban's

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10. Packaging-gateway.com, 2014, Smurfit-MBI Corrugated Container Plant

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gateway.com/projects/smurfit_mbi/. [Accessed: 20Dec 2013].

11. Paulapuro, H., 2000, Paper and board grades, Helsinki, Finland: Fapet Oy.

12. Satyamag.com, 2013, Satya April 05: Interview with Shigeru Ban. [online]

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2013].

13. Schreuders, P. D. Salmon, S. D. and Stewardson, G. A. 2008. Temporary

Housing for the Homeless: A Pre-Engineering Design Project. Technology

Teacher, 67 (4), pp. 4--10.

14. Shigerubanarchitects.com, 2013, 坂茂建築設計 | Shigeru Ban Architects.

[online] Available at: http://www.shigerubanarchitects.com/ [Accessed: 20

Nov 2013].

15. Van Dooren, E. and Van Iersel, T., 2008, A House of Cardboard, Cardboard

in Architecture, 7, p. 69.

Efficiency of Corrugated Cardboard as a Building Material

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